Presenting data in a graphical format always helps a lot in parsing the data efficiently. If the charts are interactive and linked, that's even better. Drill-down charts allow you to convert individual data plots (columns in column chart, pie slices in pie chart etc) of a chart into hotspots (or links). These items, when clicked, can open new charts and you can navigate between these charts easily.

They use the LinkedCharts feature of FusionCharts to make the graphs clickable. They set up a basic database-driven system that holds some randomly generated data for display. Full PHP and HTML are provided to create a simple chart like this where you can click into any of the bars for more detailed information. You can also download the full source or check out a demo.